Electron discharge tube



06L 1951 J. H. JONKER E'l'AL 2,571,723

ELECTRON DISCHARGE TUBE Filed June 1, 1950 INVENTORS.

avmnmswnrwuxmmnmnmz ADRIANIJS Jams mmuwmm 1170mm BYWM7 AGE VT Patented Oct. 16, 1951 2,571,723 ELECTRON DISCHARGE TUBE Johannes Lodewijk Hendrik J onker and Adrianus Johannes Wilhelmus Marie van Overbeek, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Company, Hartford,

Conn, as trustee Application June 1, 1950, Serial No. 165,406 In the Netherlands June 4, 1949 3 Claims.

Beam tubes the beam of which is adapted to occupy a plurality of fixed positions and to be held in these positions, may be used for counting pulses successively supplied to a control electrode of the tube. Consequently, such a tube is called counter tube. In most cases sucha tube has 10 fixed positions which are traversed by the beam under the action of the said pulses, the beam rushing from the last position, as a result of a subsequent pulse, into the initial position. Any desired number of pulses may thus be counted by the arrangement in series of a plurality of such tubes which indicate the units, the tens, the hundreds, etc. This is of importance for example, for telephone exchanges, electric calculating machines and the like. In order to be able at any moment to read the number of pulses already given, it is required that the position of the beam of each tube may readily be ascertained. In certain cases it is desirable that the positions of the beams of the various counter tubes are rapidly readable even from a comparatively large distance.

It is known to provide windows in an anode of an electron tube, which windows are covered with fluorescent material so as to become luminescent upon bombardment by electrons. If, however, a plurality of such windows are juxtaposed with a small spacing, each window corresponding to a figure between, for example, 0 and 9, it is diflicult to determine immediately the figure corresponding to this window. The said disadvantage is obviated if, according to the invention, in a tube in which a ribbon-like electron beam is adapted to occupy a plurality of fixed stable positions, one or more collecting electrodes of the beam is or are provided with one or more windows corresponding to the various positions of the beam, which windows become luminescent upon being struck by the beam current and are provided in a staggered manner in the direction of the greatest length of the sectional area of the beam, the dimensions of the windows in the said direction being smaller than the length of the sectional area of the beam. The height of the windows will preferably be chosen to be /3 to /3 of the length of the sectional area of the beam. The advantage of this arrangement is that space for providing a distinct figure becomes available above or below each window. It has been found that the said arrangement of the windows permits of reading the figure corresponding to the position of the beam very rapidly and even from a distance of several metres.

It is also possible even to increase the velocity of reading either by covering the various windows provided at the same level with material which becomes fluorescent in different colours, or by forming the windows themselves into the shape of figures.

The invention will now be explained more fully by reference to some examples and a drawing wherein:

Fig. 1 shows a side view of a tube according thereto, and

Fig. 2 a cross section of such a tube.

In the figures A designates the bulb, B the base with contact pins C, and D the anode surrounding the electrode system and externally'covered by a mica plate. The anode D has It] apertures or windows E, and the said mica plate F is metallised on the anode side, which metallisation M has corresponding windows 'E recessed in it. The metallised side M of the mica plate F is furthermore covered with fluorescent material G. If desired, the metallisation M at the areas of the windows may be of such thinness as to be transparent. Thi is advantageous in order to prevent the fluorescent material G and the mica F in the windows from being loaded. The window which is struck by the beam is clearly lighted so that the figure associated with the window concerned may be determined, even at a distance of several metres, from the position of the window, even if the figures provided at the windows were themselves not clearly visible, for example due to darkness. If a plurality of such countertubes are arranged in juxtaposition, in such manner that from the right to the left the tubes indicate the units, tens, hundreds, etc., the figures indicated by the tubes are readily readable.

It is also possible to form the windows into different shapes or to construct them in a different manner. Thus, the surroundings of the apertures provided in the anode may be covered with material which. becomes fluorescent under the action of electrons passing through the apertures and falling back on to the anode at the side of the apertures. It is furthermore possible to provide inclined reflecting electrodes in the vicinity of the apertures, in order that the electrons passing through the apertures may be reflected to a determined spot on the anode, in the vicinity of the aperture concerned. Furthermore, it is possible to cover the windows with a gauze or grid on which the fluorescent material is provided. The above-described embodiment, however, is simplest and produces the optimum visible effect.

- The width of the window is preferably about equal to the width of the sectional area of the beam.

What we claim is:

1. An electric discharge tube adapted to count a succession of pulses comprising an evacuated envelope and an electron discharge system contained therein and comprising an electron gun for producing a ribbon-like beam of electrons having a given rectangular cross-section, a collector electrode having a plurality of windows therein staggered in the direction of greatest dimension of the cross-section of the beam, the dimensions of each window being smaller than the largest cross-sectional dimension of the beam, a thin light-transparent target electrode on that side of the collector electrode remote' envelope and an electron discharge system contained therein and comprising an electron gun for producing a ribbon-like beam of electrons having a given rectangular cross-section, a collector electrode having a plurality of windows therein staggered in the direction of the greatest dimension of the cross-section of the beam, each of said windows having a largest dimension in the direction of the greatest dimension of the beam which is between one-third and two-thirds the length of the greatest beam dimension, a thin light-transparent target electrode on that side of the collector electrode remote from the electron gun, and portions of the target electrode on the side nearest the collector electrode and coincident with the windows of the collector electrode covered with a material which luminesces when bombarded by the electron beam.

3. An electric discharge tube adapted to count a succession of pulses comprising an evacuated envelope and electron discharge system contained therein and comprising an electron gun for producing a ribbon-like beam of electrons having a given rectangular cross-section, a collector electrode having a plurality of windows therein staggered in the direction of the greatest dimension of the beam, each of said windows having a largest dimension in the direction of the greatest dimension of the beam which is smaller than the greatest beam dimension, each of said windows having a configuration corresponding to a given figure representing one of the pulses, a thin light-transparent target electrode on that side of the collector electrode remote from the electron gun, and portions of the target electrode on the side nearest the collector electrode and coincident with the windows covered with a material which luminesces when bombarded by the electron beam.

J OHANNES LODEWIJK HENDRIK JONKERv ANDRIANUS J OHANNES WILHELMUS MARIE VAN OVERBEEK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,977,398 Morrison Oct. 16, 1934 2,053,268 Davis Sept. 8, 1936 2,266,671 Wolf Dec. 16, 1941 2,365,476 Knoop et al Dec. 19; 1944 2,465,380 Labin et a1 Mar. 29, 1949 

